Motion transformer



Oct. 13, 1959 HETZEL 2,908,174

MOTION TRANSFORMER Filed April 26, 1956 United States Patent MOTION-TRANSFORMER Max Hetzel, Biel, Switzerland,assignor to Bnlova WatchCompany, Inc., Jackson Heights, N.Y.

Application April 26, 1956, Serial-No. 580,813 Claims priority,application Switzerland October 23, 1953 13 Claims. (Cl. 74-128) Thepresent invention relates to a motion transformer.

More particularly, the present invention relates to an electrictimepiece incorporating a motion transformer capable of transforming theoscillations of a vibrator into rotary movement, the electric timepiecebeing of the type disclosed in copending applications Serial No.436,949, filed June 15, 1954, now abandoned, Serial No. 547,510, filedNovember 17, 1955, now abandoned (said application Serial No. 547,510being a continuation of application Serial No. 463,462, filed October20, 1954, now abandoned), Serial No. 565,451, filed February 14, 1956,Serial No. 565,452, filed February 14, 1956, and Serial No. 570,958,filed March 12, 1956.

It is an object of the present invention to provide an electrictimepiece which incorporates a motion transformer adapted to transformthe oscillations of a vibrator into the rotary movement of the hands ofthe timepiece.

It is another object of the present invention to provide an electrictimepiece wherein the action of the vibrator is controlled in such amanner as to insure the accuracy of the timepiece.

The objects of the present invention further include the provision of anelectric timepiece which is composed of simple and ruggedly constructedelements which are very reliable in operation.

It is still another object of the present invention to provide anelectric timepiece which may be mass produced at low cost.

With the above objects in view, the present invention mainly consists inthat improvement in a timepiece which incorporates a mechanism fortransforming vibration into a rotary motion, the mechanism including asupport means, rotary means mounted on the support means for rotationrelative thereto, a vibrator mounted on the support means, driving meansconnected to the vibrator for movement therewith and frictionallyengaging the rotary means for turning the latter, and means operativelyassociated with the rotary means for limiting the same to one directionof rotation.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. ,Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings, inwhich:

Fig. 1 is an elevational view of one form of the invention,

Fig. 2 is a section on the line IIII of Fig. 1,

, Fig. '3 is an elevational view of another form of the invention, and

Fig. 4 is an elevational view of a constructional detail applicable toeither of the two forms of invention shown.

The mechanism shown in Fig. 1 comprises the ratchet wheel 1, which isfulcrumed at 2 and which forms part 2,908,174 Patented Oct. 13, 1959 iceof a watch or clock mechanism. A' mechanical vibrator 4 oscillates inthe direction of the arrows A and A. Above wheel 1 is disposed a wire 5of which one end is fixed to the vibrator 4 and of which the other endis connected to a coil spring 6 fixed to a portion 8 of the case of theclockwork. Spring 6 is fixed to case 8 by one of its ends beingintroduced into a bore provided in case 8, the spring being retained insaid bore by means of a tapered pin 14. Such disposition not onlyprovides a resilient coupling of the wire with vibrator, but alsopermits to regulate the tension of spring 6, and, thus, the tension ofwire 5 by shifting the spring-end in case 8. When the vibrator 4oscillates, wire 5 also oscillates.

On wire 5 and in engagement with wheel 1 is disposed a friction element7 so that the underside thereof bears with slight pressure on the teeth3 of wheel 1. Element 7 is made of a very light material and, as may betaken from Fig. 2, is provided over its entire length with a groove 7 ofwhich the sidewalls are inclined towards the interior thereof, and inwhich the wire 5 is engaged.

Owing to the friction between wire 5 and the sidewalls of groove 7', theelement 7 normally participates in the vibrations of wire 5. But when,for any reason whatever, element 7 is prevented from moving, wire 5slides in groove 7'. The movements of element 7 are limited on bothsides by two stops of which one, 9, is fixed to case 8 at a distance dfrom that end of element 7 which points towards vibrator 4, and theother stop, 10, is fixed to the case 8 at a distance d from the otherend of the element.

The underside of element 7, extending longitudinally to the wire 5 andtangentially to the ratchet wheel, bears on the teeth 3 of ratchetwheel 1. In the form of invention described, the underside of theelement is covered by a plastic material 11 (Fig. 2). The latter servesfor the purpose of improving the friction between the underside of theelement and the teeth of the wheel and of preventing a rapid wear ofsaid underside.

On a portion 13 of the case of the clockwork is mounted a pawl 12 formedby a very thin resilient leaf, preferably made of a plastic, of whichthe free ends bear with a slight pressure on a tooth 3 of wheel 1.

When vibrator 4 swings in the direction of arrow A, wire 5, being fixedthereto, moves in the same direction, stretching spring 6 and carryingaway element 7. The underside of the latter, bearing on the teeth 3,turns wheel 1 through a certain angle in the direction of arrow B. Atthe same time, pawl 12 slides off a tooth 3 and abuts against thefollowing tooth. When vibrator 4 swings in the direction of arrow A,wire 5 through the action of spring 6 is returned into its initialposition carrying away with it element 7. But during such movement pawl12 abuts against a tooth 3 of wheel 1 and thus prevents the latter fromturning in the direction opposite to arrow B. Owing to the resilience ofthe suspension of element 7, the underside of the latter slides on theteeth 3 of wheel 1.

Inorder that the device described above may function in a satisfactorymanner, it is important that element 7 turns wheel 1 always through thesame angle, independently of the amplitude of oscillation of vibrator 4and wire 5, which amplitude from accidental causes may not be constant.To such end, the two stops 9 and 10 maintain the reciprocations ofelement 7 within limits which have exactly been predetermined.

On the other hand, the device described being destined to actuate aclockwork, wheel 1 each and every time has to rotate through an anglecorresponding to the pitch p of the teeth 3. Fig. 1 clearly shows thatthe conditions are satisfactory when the total displacement of d+d' of 3element 7 is greater than pitch p but less than 2p, or in other words,when '2p d+d p.

It further is obvious that the amplitude A of oscillations of vibrator4has to bemaintained greaterthan the value of pitch p, but wheel 1still'inust'be capable of rota-' 7, spring 6 an'd'wheel 1, be higherthan'the frequency of oscillationof the mechanical vibrator As has beenset forth above, wire is engaged in groove 7"by simple friction in orderto dampthe shocks of elemerit-7 strikingagainstthe stops 9 and 10, sothat the wire may slide in groove 7. r

In another form of invention, shown in Fig. 3, the wire 5is fixed to theelement 7. In order to damp the shocks when the latter abuts against oneof the stops 9 or 10, the'wire is connected to vibrator 4 through asecond coil spring 15. As in the first form of invention,- the naturalfrequency of spring must be higher than that of the oscillations ofvibrator 4. The device shown in Fig. 3 otherwise issimilar to that shownin Fig. 1.

In the two forms of invention described, wire 5 is so disposed thatelement 7 bears on wheel 1 with sufiicient pressure tolimpart a rotarymovement thereto. In some special cases it maybe desirable to exert apressure on element 7 in order to ensure contact between the element andthe teeth of the ratchet wheel during the active movement of theelement. Such positive contact may be attained by means of theconstruction shown in Fig. 4. An arched leaf spring 16 fixed at one endon the case to a pin 17 bears with its free end on the upper side ofelement 7. Spring 16 is convex towards vibrator 4 so that, Whenelement 7moves in order to rotate Wheel 1, spring 16 tends to increase itspressure, while, whenelement 7 moves in the other direction, thepressure of the spring 1 6 tends to decrease.

What is claimed is:

l. A mechanism for transforming mechanical vibrations of a vibrator intoa rotary movement for actuating a watch or clock mechanism including aratchet wheel, comprising a wire resiliently coupled to the vibrator andvibrating therewith, a friction element associated to said Wire, oneside of said element extending longitudinally of said wire andtangentially to said ratchet wheel, bearing on some of the teeth of saidratchet to cause rotation of said wheel in one direction, a pawlcoacting with the teeth of said wheel so as to prevent the latter fromrotating in the other direction, means for defining the movements ofsaid element within predetermined limits independently of the amplitudeof said vibrator, and means for damping the shocks of said element.

2. A mechanism as set out in claim 1, in which the resilient couplingbetween said wire and vibrator is constituted by a coil spring connectedat one end to said wire and at the other end to the vibrator.

3. A mechanism as'set out in claim 1, in which the connection betweensaid wire and element is' attained by the friction of the wire in alongitudinal groove provided in the element, the wire being capable ofsliding in said groove when the element is prevented from moving.

4. A mechanism as set out in claim 1, in which said element is rigidlyfixed to the vibrating wire, and a spring is provided between the wireand the vibrator for damping the shocks of said element.

5. A mechanism as set out in claim 1, in which the means for limitingthe movements of the element are constituted by two stops disposedadjacent to'the two ends of said element at a distance therefrom equalto d and d respectively, so as to satisfy the relation 2P d+d' P,wherein P is the tooth pitch of said ratchet wheel.

6. A mechanism as set out in claim 1, in which the element-undersidewhich bears on the teethof said wheel is provided with a lining'ofplastic.

pawl is constituted by a resilientgleafof which one end 7. A mechanism.asyset outjin claimjl, in which the' pitch of the teeth ofv said wheelis-smallerthan the maximum amplitude of the oscillations of saidvibrator. 8. A mechanism as set out inclaim l, in'which said is fixed toa fixed support and theother end bears on a tooth of said wheel.

9. A mechanism as set out in claim 8, in which said pawl is constitutedby a leaf made of plastic.

10. A mechanism as set out in claim 1 in; which means are provided forexerting a pressure on said element in order to maintain the latter insaid ratchet wheel.

11. A mechanism as, set out in claim 10, in which said:

. means are constituted by an arched leaf spring of which,

one end is fixed to a fixed support, and of which the other end bears onthe upper side of said element, said.

leaf spring being sodisposed as to increase the pressure on the elementwhen thelatter moves in order to turn said wheel, and to decrease saidpressure when the element moves in the other direction. h

12. A mechanism for transforming m echanical vibrations of a vibratorinto -a rotary movement for actuating a Watch or clock mechanismincluding a ratchet wheel,

1 comprising a wire c'oupledto the vibrator'and vibrating,

therewith, a friction element associated with said wire, one side ofsaid element extending longitudinally of said wire and tangentially tosaidiat'chet wheel,- bearing on, some of the teeth of said'ratchet tocause r'otation of said wheel in one'direction, a pawl coacting with theteeth of tary motion, c0mprising,in combination, a ratchet wheelturnable' about its axis; a friction block having one face in frictionalengagement with a peripheral portion of said ratchetwheel and havinganother face opposed to said one face and formed with an elongatedchannel extend ing substantially along said peripheral portion of saidratchet wheel; an elongated wire extending through andbeyond oppositeends of said channel and engaging said block at a part of said channelnearest to said ratchet wheel; vibrating means connected to one end'of'said-wire' located beyond said block; and resilient means connectedto an opposite end of said wire located beyond said block.

1 References Cited in the file of patent: UNITED STATES PATENTS1,290,264 McDonald June 7,1919 1,816,102 Waters et al. J u1y"28, 19312,196,189 Bott Apr. 9, 1940 FOREIGN PATENTS: 761,633 19 56,

Great Britain t 514,-

contact with the te th or.

